Navigators have known for thousands of years that the ocean has variable currents, but it is only in the last half century that a reasonably clear picture has emerged of the patterns and causes of ocean currents.
A.a reasonably clear picture has emerged of the patterns and causes of ocean currents
B.a reasonably clear picture of the patterns of ocean currents and their causes have emerged
C.a reasonably clear picture emerged of ocean currents, their patterns and the causes of them
D.there have emerged a reasonably clear picture of the patterns of ocean currents and what caused them
E.there had emerged a reasonably clear picture of the patterns of ocean currents and their causes
为啥选A呢？？ 谢谢谢谢大家，告诉告诉俺吧(搜过历史贴）
作者: AlienX 时间: 2009-4-12 12:10
B: have錯 C: 改變原意; emerged應該是has emerged D: have錯 E: had錯 ==================== 很久巳前有個NN說of the patterns and causes of ocean currents被後置了. a reasonably clear picture of the patterns and causes of ocean currents has emerged. 至於為什麼可以這樣後置, 我不知道. 做了這麼多official SC questions, 發現了很多不規則的(可能是我自己沒看出規則)前/後置東東(e.g. OG12#1), 所以個人覺得, 考時候看到沒見過的前/後置的用法, 不要當錯... 作者: AlienX 时间: 2009-4-13 06:21
一題老OG題...後置twice: American productivity is declining in relation to Europe’s; the energy expended per unit of production in the United States is as much as twice that expended in West Germany.作者: shuxuehai 时间: 2009-4-14 07:12
这题有2个问题： 1。为什么要用完成时态？后半句的状语是in the last half century，应该是过去时态的标志吧？ 2。我道觉得B对，因为，picture of ocean currents可以理解，但是picture of causes如何理解？所以我觉得是，picture of ocean currents和causes并列做主语。 请NN指正思路上的错误。。。谢谢。 作者: AlienX 时间: 2009-4-14 07:32
NYTimes: A team from the National Transportation Safety Board was dispatched to investigate the incident, though it was expected to be days and perhaps weeks before a clear picture of the cause would emerge.
but it is only in the last half century that a reasonably clear picture has emerged of the patterns and causes of ocean currents. it is...that...是强调句型，
此句还原后是 a reasonably clear picture has emerged of the patterns and causes of ocean currents only in the last half century. in the last half century 要用现完成时
作者: xinling917 时间: 2009-9-6 22:03
in the last half century为什么不用一般过去时呢？难道那个picture的出现要持续到现在么？？？作者: xinling917 时间: 2009-9-6 22:09
看了大牛的解释明白了！
“难道'in the last century' 表示的是大段时间,而不是一个时间点?
LZ说得很对。
with in the past/last/recent N years (N代表一个数或一段时间)